The present invention is directed to a wedge anchorage for the end of a single tension member within a prestressed concrete structure to which tensioning means are attached. The tension member is completely enclosed within and spaced inwardly from the surface of the concrete structure. The anchorage is provided by an anchor member and a wedge seated within the anchor member. The anchor member has an axially extending passage for the tension member with the passage having a conically widening surface forming a seat for the correspondingly shaped wedge.
Such a wedge anchorage is known in the Swiss patent No. 482 080. In this patent publication the tension members have two anchorages where the tension forces are transferred to the concrete structure with the members forming the anchorages embedded in the concrete structure. One anchorage is designed as a so-called fixed anchorage and is completely encased in the concrete structure, the other anchorage at the end where the tension forces are applied must remain accessible until after the tensioning is carried out, so that a tensioning stress or prestressing jack can connected to the end of the tension member.
To apply tension to the tension member a recess must be provided in the concrete structure for the prestressing equipment. After the prestressing is effected, the recess must be closed off to prevent corrosion. The closure for the recess is mainly provided by a cement mortar plug so that the anchorage located within the recess is completely enclosed within the concrete structure. Disregarding the fact that the recess must be formed and subsequently sealed off, a dependable corrosion protection can be obtained only with considerable difficulty, since there is always the possibility of shrinkage of the cement mortar plug causing it to separate from the recess whereby moisture can enter and penetrate to the tension member and its anchorage. It is known in fixed anchorages to provide the anchor member at the point where the tension member passes out of the anchorage with a cap. A compression spring is located within the cap and surrounds the end of the tension member extending through the wedge and affords a frictional locking connection between the cover of the cap and the end face of the wedge for securing the wedge in position, note Swiss patent No. 482 080. It is also known to provide projecting means inside the cap arranged so that they extend into connection with the wedge and fix the wedge in position when the cap is threaded on to the anchor member, note German Utility Model No. 80 02 044.
Another arrangement is disclosed in German Offenlegungsshrift No. 25 06 395 where a plurality of wedge connections are provided in a common anchor member. There is no special noncorrosive covering for the anchorage and the tension member illustrated.